Don't use the third field of llvm.global_ctors for MachO.

The field is defined as:

If the third field is present, non-null, and points to a global variable or function, the initializer function will only run if the associated data from the current module is not discarded.

And without COMDATs we can't implement that.

llvm-svn: 218097
diff --git a/clang/lib/CodeGen/CodeGenModule.h b/clang/lib/CodeGen/CodeGenModule.h
index b36d4a6..a095c9d 100644
--- a/clang/lib/CodeGen/CodeGenModule.h
+++ b/clang/lib/CodeGen/CodeGenModule.h
@@ -599,6 +599,9 @@
   DiagnosticsEngine &getDiags() const { return Diags; }
   const llvm::DataLayout &getDataLayout() const { return TheDataLayout; }
   const TargetInfo &getTarget() const { return Target; }
+  const llvm::Triple &getTriple() const;
+  bool supportsCOMDAT() const;
+
   CGCXXABI &getCXXABI() const { return *ABI; }
   llvm::LLVMContext &getLLVMContext() { return VMContext; }